Tube expansion tool



April 26, 1966 FIG. I

H. E. LINTHICUM ETAL TUBE EXPANS ION TOOL Original Filed Aug. 17, 1962 FIG. 2 A

IN VEN TORS; HARLEY E. LINTHICUM. WILLIAM A. LINTHICUM.

ATTORNEY.

Unit d St OfiiC? 3,247,695 Patented Apr. 26, 1966 1 Claim. '(Cl. 72-122) This application is a division of our copending application Serial-No. 217,747, filed August 17, 1962, entitled, Tube Expansion Tool, and relates to a method of expanding a portion of a tubular member for the purpose of uniting it 'with a structural part having a preformed aperture for receiving the tube. I

Tools of the type to which this invention relates are employed for thepurpose of expanding with a rolling action the ends of tubular members into tube support sheets as, for illustration, in heat exchange equipment. The portion of the tube to be united with the tube sheet is expanded in a radial direction into tight mechanical connection with an aperture in the support sheet for receiving the tube. The action employed in causing the union between the tube and the sheet is referred to as tube rolling and is accomplished by forcing a series of roller elements outward against the inner surface of the tube by a mandrel member constructed so that the outward movement of the rollers is controlled.

When it is desired to unite relatively small diameter, thin wall tubes with tube support sheets, the power requirement of the tool, represented by the torque necessary to force the tubular member outward, is at a minimum. It has been discovered that under these conditions the housing accommodating the roller elements usually re ferred to as the cage, may be connected directly to the power source so as to be rotated therewith. Normally, the mandrel member is connected to the power source and is rotated thereby.

Accordingly, the chief object of this invention is the provision of a tool of the kind described wherein the cage member housing the roller elements is connected directly with the source of power providing rotary motion of the type necessary to impart rotational motion to the roller elements assembly within the housing. With such an arrangement the mandrel is freely rotatable within the housing and may be advanced by the action of the roller elements when the tool engages the work.

An additional object of the invention is the provision of an improved tool of the kind contemplated, wherein, the mandrel member is normally arranged within the housing accommodating the roller elements in such a manner that movement of the mandrel in the housing neces sary to produce the rolling force is accomplished against the action of the spring. This arrangement has the advantage of causing prompt retraction of the mandrel into the housing at the conclusion of use.

A further object of the invention is the provision of a tool for expanding tubes in which there are means provided for yieldably adjusting the position of the mandrel within the housing so that a controlled amount of outward movement of the roller elements may take place prior to the engagement of the tool with the work.

A still further object of the invention is the provision of a novel method of uniting a tubular member and a structural support part wherein rotational motion is provided directly to the housing under the circumstances where the roller elements will pick up and advance the mandrel longitudinally of the housing against the action of the resilient spring member.

These and other objects of the invention will be apparj 2 cut upon consideration of th ensuing specification and drawings in which:

FIGURE 1 is an elevational View, partly in section, illustrated a tool constructed in accordance with this invention; and I FIGURE 2 is a fragmentary view illustrating the action of the roller elements as they engage the work. H

Referring more particularly to the drawings for an illustration of a preferred embodiment of the invention, there is shown a roller support member 10 serving as a housing for the operating parts of the tool which is provided with a differential passage 12 extending therethrough. The portion 14 of the passage 12 shown to the right of the tool is provided with the largest diameter and is threaded for a purpose to be later described. Passage 12 through the roller Support member includes a section 16 of intermediate diameter and a section 18 of a smaller diameter, the latter two sections being defined by shoulder 20.

At the end of the roller support member 10 remote from the portion 14, there is provided a plurality of circumferentially spaced slots 22 arranged in a skewed direction relative to the longitudinal axis of member 10. Disposed in each slot 22 is a roller element 24.

Assembled within the roller support member serving as the housing is a mandrel 26. The mandrel includes a first tapered end portion 28 which terminates in a portion 30 of constant diameter. Located axially adjacent portion 30 is an intermediate portion or section 32 having a relieved configuration for a purpose to be later described. End section 34 of a diameter similar to the portion 30 completes the mandrel which is provided with a cap 36 arranged to snugly engage bushing 37 arranged in portion 16 of the passage through the roller support member.

A spring 38 is arranged so as to engage the shoulder 20 and the bushing 37 for the purpose of urging the mandrel to its retracted position shown in the drawing. An adjustable abutment member 40 is threadablymounted within section 14 of passage 12 for the purpose of adjusting the position of the mandrel relative to the rollers against the action of the spring 38.

Considering the operation of the tool .forming the invention, with the tool penetrating the open end of the tube, adjustable abutment member 40 is manipulated so that the mandrel 26 forces the roller elements 24 into engagement with the inner surface of the tube, see enlarged FIGURE 2, as it rests in the opening in the sheet to which it is to be joined. The end of the tool having the threaded surface 14 is connected to -a. suitable power source which then supplies rotary motion directly to the roller support member 10.

With the parts in engagement as described, the member 10 is rotated carrying the rollers 24 with it. The action of the rollers arranged as they are relative to the end 28 of the mandrel causes the mandrel to advance from the housing against the action of spring 38.

The advance of the mandrel provides a camming action forcing the roller elements into engagement with the inner surface of the tube to deform it into a tight bond with the surface of the support member defined by the opening accommodating the tube.

Travel of the mandrel continues until the section 32 of the mandrel is in registry or alignment with the rollers 24. At this point, the rollers drop inwardly and the rolling action is terminated. The operator then withdraws the assembly from the Work and the action of the spring 38 retracts the mandrel to the position illustrated in the drawing.

With the assembly shown, the member 10, sometimes referred to in the art as the cage, is rotated directly by its connection with the power source. Due to tube wall variations, the tube I.D. becomes a variable. For proper action the tool should engage with the unrolled tube I.D. somewhere between the front end of the roll and center (lengthwise). This can be assured by adjusting position of element 40 which in turn, positions mandrel 28 relative to rollers 24. With the construction described the tool action is rapid and precise resulting in considerable economy of operation. The enlargement of the tube is limited by the configuration of the parts and the positioning of the mandrel section 28 relative to the roller elements accurately determined and maintained by the action of spring 38 and abutment member 40.

The above disclosure has been given by way of illustration and elucidation, and not by way of limitation, and it is desired to protect all embodiments of the herein disclosed inventive concept within the scope of the appended claim.

We claim:

In the method of uniting a tubular member with a structural part having an opening for receiving said member by displacing the inner surface of the portion of said member with roller elements arranged in a housing, wherein said roller elements are forced outwardly by an advancing tapered mandrel so as to radially expand said member into engagement with said part the steps 2 which consist of:

5 yieldably adjusting said tapered mandrel relative to said roller elements until engagement between said roller elements and said tapered mandrel occurs sufficiently to cause engagement between said roller elements and said member; and

10 imparting rotary motion directly to said housing and thereby to said roller elements suificiently to cause advancement of said tapered mandrel by the action of said roller elements simultaneously with the application of outward force by said roller elements 15 of a magnitude to cause radial displacement of said member into engagement with said part.

References Cited by the Examiner UNITED STATES PATENTS 8/1933 Duchesne 15382 2/1951 Fitzgerald 15382 CHARLES W. LANHAM, Primary Examiner. 5

H. D. HOINKES, Assistant Examiner. 

